1. Field of the Invention
This invention relates to the identification of circuit wiring utilized to feed electrical power to the sockets of florescent lamps from the electric ballasts of advertising signs.
2. Description of the Prior Art
Advertising signs utilizing electric lamps, particularly florescent lamps positioned within the interior of the sign to illuminate the translucent sign display panel(s) are widely used today. The florescent sign lamps each have two ends each with exposed electrically conductive terminals so as to be able to receive electricity from a matched set of lamp sockets and thereby be electrically powered and illuminated. One end of each florescent lamp is removably connected to one lamp socket affixed in the interior of the sign, and the other end of each florescent lamp is connected to a second lamp socket at the other end of the sign. The ends of a florescent lamp typically have an interior electrode which is used for starting the arc for causing illumination. The lamps may be positioned vertically or horizontally in the sign. One of the lamp sockets of a matched set of sockets is movable inward and outward, being spring biased toward the outward position so the lamp may be inserted and retained between the two sockets, and then removed when desired. This type of movable lamp socket is commonly referred as a "live end" socket, and the non-movable lamp sockets are commonly referred to a "dead end" sockets. Each florescent lamp is connected to two sockets, and the sockets are connected to the interior of the sign in spaced apart relationship to one another to allow for the removable connection of the elongated lamps. The sockets have lamp receiving recesses for mechanically stabilizing and retaining the lamps, and the recesses are fitted with exposed electrical terminals positioned for receiving the lamp ends and mating with the electrical terminals of the lamps. The rearward or base portion of each lamp socket is specifically shaped and affixed with spring biased holding tabs for affixing the socket removably and stationary to a panel defining a portion of a wire raceway of the sign. Each socket additionally has at least one, and most often two insulated flexible electrical conductors or wires leading and connecting to the exposed electrical terminals on what is considered the front of the sockets. These socket wires are normally about 8 inches in length. The rearward or base ends of the sockets, the location at which the wires exist the sockets, are shaped relative to an aperture in the raceway to allow removable snap-in attachment of the sockets to the raceway. Often the socket receiving apertures are placed in the removable cover of the raceway so the sockets may be removably secured to the raceways with the fronts of the sockets positioned to receive a lamp end on one side of the raceway cover, and the rearward or base end of the sockets with extending wires being positioned on the opposite side of the raceway cover so the socket wires may be fully contained within the raceway when the raceway cover is installed over the open interior of the raceway. The containment of wires in a raceway is primarily for fire and human safety purposes. Normally, a sign will have a raceway with a removable raceway cover at each end of the sign within the interior of the sign adjacent each end of the lamps, and some signs have raceways access covers on the exterior of the sign. With the cover removed from the raceway, the open interior of the raceway is exposed. Within the interior of the raceway are electrical extension wires which connect by way of splicing, usually with wire-nuts, to the short wires extending from the rearward ends of the sockets. The extension wires within the raceway extend within the raceway from their connections to the wires of the lamp sockets through the raceway and connect to the relatively short load side wires of a lamp ballast. Signs with florescent lamps utilize electric ballasts which serve as voltage transformers and power regulators for driving the florescent lamps.
Lamp ballasts are available from many manufacturers in many internal circuitry configurations for driving various lengths of florescent lamps by the ballast. Very often, but not always, a single ballast will include circuitry and accessible load side wires to allow the installer to use that ballast in a number of different arrangements such as to drive two lamps, four lamps, or six lamps, and many common ballasts are rated to operate a range of lamp lengths. A given ballast may power any arrangement of lamps between 16 and 32 total lamp footage for example, depending on how the wiring and lamps are circuited, and this is to reduce the number of ballasts a sign manufacturer must stock in the shop or on a service truck. Some signs use more than one ballast, and normally when two or more ballasts are used in a sign, the sign is logically zoned wherein a ballast mounted high in the sign will drive horizontally positioned lamps high in the sign, and a ballast mounted low in the sign will drive lamps positioned low in the sign. The same logical zoning in a sign holds true with vertical lamps wherein a ballasts placed in the left powers lamps in the left of the sign.
In any case, ballasts have at least two line side conductors, and normally at least four load side conductors, and many common ballasts have anywhere from three to fourteen load side conductors. The load side conductors are normally marked or coded into matched pairs of conductors wherein a matched pair is for connecting to and powering one lamp socket of a matched set of sockets. A second matched pair of load side conductors is for connecting to and powering the second lamp socket of the matched set of lamp sockets. Normally a set or matched pair of load side conductors are each of the same color or coding, and the set or matched pair of conductors for the opposite socket are of the same color or coding as each other, but of a different color than the set of load side wires on the other socket of the set of sockets. For example, two black wires might feed one socket of a set of sockets, and two red wires might feed the second socket of the set of sockets for powering a single florescent lamp.
Color-coding is by far the most common form of coding currently used for load side wires of a ballast, however, coding by numbers has been used in rare instances in the past, and is similar to that commonly used in multi-voltage poly-phase electric motors. The load side wires of ballasts are normally quite short, ranging normally between six inches to six feet in length. The coding, namely color-coding of the load side conductors of the ballast is normally indicative of the relationship of the conductor tap to the windings within the ballast, and the individual ballast manufacturers determine the particular color-coding to be applied to their load side conductors and the schematic diagrams indicating via the color-coding as to how to connect the load side conductors to lamp sockets. Ballasts typically include the schematic wiring diagrams affixed to the front of the ballast showing the often many ways the ballast can be utilized to drive different lengths of lamp arrangements. In these different lamp arrangements, windings of the ballast which have color-coded load side conductors connected thereto, may be connected through the florescent lamps, with the particular connections being in part determined by the total lamp footage desired to be powered. Improper connections to the lamp sockets and thus lamps, and the load side conductors of a ballasts, will result in lamps not illuminating properly, or ballasts or lamps becoming defective (burning out) prematurely.
Ballasts are normally mounted in the interior of the sign, and the raceway or raceways abut the ends or fully enclose the ballasts and extend between the ballast load side wires and the wires on the rearward side of the lamp sockets. The load side wires of the ballasts are very often not of sufficient length to reach the short conductors of the lamp sockets, since signs vary widely in size, and some signs are quite large. When a sign is manufactured, insulated electrical wires are spliced between the relatively short load side wires of the ballasts and the relatively short load side wires of the lamp sockets. The wires of the sockets are normally not of any particular color-coding, and most often are all the same color, and most commonly white today. The load side wires of the ballast are generally always color-coded by the ballast manufacturer, however, different ballast manufacturers use different color-codings, since there is no apparent industry standard for color-coding of a given set of load side conductors representing given winding circuit tap locations within a ballast. When the sign is manufactured by the sign manufacturer, the extension wires ran between the socket wires and the ballast load side wires may be color-coded to match the coloring of the load side wire to which the extension wire connects to, but very often are not, wherein they would all be one color such as black for example. Electrical current will flow regardless of the color of the dielectric insulation over the conductors, and during the manufacturing of a sign, the raceway covers are removed, and thus it is simple to extend the ballast load wires to the socket wires without too much confusion, whether the extension wires match the color-coding of the ballast load wires or not. The completed sign is delivered to the job site, then mounted, and the primary or line side of the ballast is connected to a suitable electrical power source for powering the ballast and thus the lamps. The sign will operate whether the color-coding has been maintained throughout the sign or not, as long as the electrical circuitry is correct.
However, in the future, when the sign needs repair due to a failure of some or all of the lamps to illuminate, which is usually after a few years, the serviceman will have a difficult time determining which ballast load side conductors feed which lamp sockets, and this information is very often crucial to the quick trouble shooting of an inoperative sign. This difficulty for the serviceman will exist whether color-coded wires were used throughout the sign or not, due to most or all of the wiring in the raceways being obscured from view by the opaque nature of the wire raceways and raceway covers, which are manufactured of panels of sheet metal. In order to trace the wiring from the ballast to determine which conductors feed which lamp sockets, it often requires the serviceman to remove all lamps from the sign in order to open the raceways to expose the wiring in the raceways. With the raceways open, the raceway covers will hang on the wiring, and so it is not normally necessary to disconnect all of the wiring connections made by wire-nuts. At this point in the servicing procedure, if the color-coding had been carried throughout the wiring of the sign in accordance with the ballast load side conductor coding and schematic, then the serviceman will have little further difficulty in the tracing of the wiring. However, it requires a significant amount of time to remove all lamps and raceway covers from a sign, particularly if the sign is mounted a significant distance above the ground, and the serviceman is working from a small lift-bucket of a crane or hoist. Furthermore, if the color-coding has not been carried throughout the original sign wiring, even with the lamps and raceway covers removed, the serviceman will spend quite a bit of time tracing the wiring since there typically exists many wires entwine with each other in a raceway.
Additionally, even if the serviceman knows the existing ballasts is burned-out, such as by testing the ballasts prior to removing any lamps and raceway covers, very often a ballast is replaced with a different make and model of ballast, and due to the non-standardized color-coding of the load side wiring from one manufacturer to another, the serviceman may still need to remove all of the lamps in order to remove the raceway covers so he may determine which load side wires of the old ballast connect to which lamp sockets in order to allow him to quickly make the correct electrical circuit connections to the new replacement ballast. Some signs have removable raceway covers placed relative to the lamp sockets which allow removal of the raceway cover without having to remove the lamps, however, it still requires a significant amount of time to remove raceway covers, particularly when they are affixed to the raceway by a large number of screws.